Chapter 9: Human Biology (Digestive System)

Question 1

mouth

Answer 1

the organ of the digestive tract where food is chewed and mixed with saliva

Question 2

tongue

Answer 2

functions as a digestive organ by facilitating movement of food during mastication and assisting swallowing, other important functions include speech and taste

Question 3

teeth

Answer 3

grinding and breaking up food

Question 4

salivary glands

Answer 4

glands that produce saliva to keep the mouth moist and to begin the process of digesting starch

Question 5

pharynx

Answer 5

a funnel-shaped passageway that connects the nasal and oral cavities to the larynx

Question 6

epiglottis

Answer 6

a flap of tissue that prevents food from passing into the larynx

Question 7

esophagus

Answer 7

a long muscular tube that is ordinarily collapsed, but opens and receives the bolus when swallowing occurs

Question 8

cardiac sphincter

Answer 8

prevents acidic contents of the stomach from moving upward into the esophagus

Question 9

stomach

Answer 9

an organ that receives food from the esophagus, starts the digestion of proteins, and moves food into the small intestine

Question 10

pyloric sphincter

Answer 10

acts as a valve to controls the flow of partially digested food from the stomach to the small intestine

Question 11

duodenum

Answer 11

the first part of the small intestine, where chyme enters from the stomach

Question 12

liver

Answer 12

largest gland in the body, produces urea and bile, detoxifies blood, stores glycogen, and produces plasma proteins, among other functions

Question 13

gall bladder

Answer 13

organ attached to liver that serves to store and concentrate bile

Question 14

pancreas

-5 things it produces

Answer 14

digestive organ with with endocrine and exocrine functions; produces pancreatic juice containing sodium bicarbonate and digestive enzymes, secretes insulin, glucagon, and somatostatin

Question 15

small intestine

- list 3 parts and give function (2)

Answer 15

consists of the duodenum, jejunum, and ileum; completes the process of food digestion and absorption of nutrients that will enter the blood capillaries or the lymphatic capillaries.

Question 16

appendix

Answer 16

small projection from the cecum; plays a role in fighting infection

Question 17

large intestine

Answer 17

includes cecum, colon, rectum, and anal cavity; absorbs water, salts, and some vitamins and store indigestible materials until it is eliminated as feces

Question 18

rectum

Answer 18

temporary storehouse for feces

Question 19

anus

Answer 19

opening of the rectum where the expulsion of feces occurs

Question 20

salivary amylase

• produced by
• site of action
• which macromolecule is broken down by it
• optimum pH
• digestion

Answer 20

• salivary glands
• mouth
• carbohydrates
• neutral
• starch + H2O –> maltose

Question 21

pancreatic amylase

• produced by
• site of action
• which macromolecule is broken down by it
• optimum pH
• digestion

Answer 21

• pancreas
• small intestine
• carbohydrates
• basic
• starch + H2O –> maltose

Question 22

maltase

• produced by
• site of action
• which macromolecule is broken down by it
• optimum pH
• digestion

Answer 22

• small intestine
• small intestine
• carbohydrates
• basic
• maltose + H2O –> glucose + glucose

Question 23

pepsin

• produced by
• site of action
• which macromolecule is broken down by it
• optimum pH
• digestion

Answer 23

• gastric glands
• stomach
• proteins
• acidic
• protein + H2O –> peptides

Question 24

trypsin

• produced by
• site of action
• which macromolecule is broken down by it
• optimum pH
• digestion

Answer 24

• pancreas
• small intestine
• proteins
• basic
• protein + H2O –> peptides

Question 25

peptidases - produced by - site of action - which macromolecule is broken down by it - optimum pH - digestion

Answer 25

- small intestine - small intestine - proteins - basic - peptide + H2O --> amino acids

Question 26

nuclease - produced by - site of action - which macromolecule is broken down by it - optimum pH - digestion

Answer 26

-pancreas -small intestine -nucleic acids -basic RNA and DNA + H2O --> nucleotides

Question 27

nucleosidases - produced by - site of action - which macromolecule is broken down by it - optimum pH - digestion

Answer 27

- small intestine - small intestine - nucleic acids - basic - nucleotide + H2O --> base + sugar + phosphate

Question 28

lipase - produced by - site of action - which macromolecule is broken down by it - optimum pH - digestion

Answer 28

- pancreas - small intestine - lipids - basic - fat droplet + H2O --> glycerol + fatty acids

Question 29

swallowing

Answer 29

a process that occurs in the pharynx, is a reflex action performed automatically, without conscious thought. The soft palate moves back to close off the nasopharynx and the trachea moves up under the epiglottis to cover the glottis. During swallowing, food normally enters the esophagus because our air passages are blocked. We do not breathe when swallowing.

Question 30

peristalsis

Answer 30

rhythmic muscular contractions that push food along the digestive tract. It begins in the esophagus and continues through all the organs of the digestive tract.

Question 31

gastric juice - contains what three things - what gets converted when exposed to HCL - ^ how and what does this breakdown? - describe pH and benefits - explain how it physically helps digestion

Answer 31

contains pepsinogen, hydrochloric acid (HCl), and mucus. Pepsinogen becomes the enzyme pepsin when exposed to HCl. Pepsin helps to break down proteins in peptides. The high acidity of the stomach (about pH 2) is also beneficial because it kills most of the bacteria or other microbes present in food. The juice helps break food into smaller pieces in the stomach as it churns.

Question 32

pancreatic juice - contains what two things - where can it be found

Answer 32

contains sodium bicarbonate (NaHCO3) to help neutralize stomach acid, and digestive enzymes for all types of food. The juice moves into the duodenum and completes the process of food digestion.

Question 33

intestinal juice - contains what three enzymes - function

Answer 33

contains maltase, peptidases, and nucleosidases. It is involved with the processes of the small intestine, including digestion of foods.

Question 34

insulin

Answer 34

The pancreas secretes insulin from the beta endocrine cells of the pancreatic islets. Insulin is secreted when blood glucose level is high, which usually occurs just after eating. It stimulates uptake of glucose by cells, especially liver cells, muscle cells, and adipose tissue cells. In liver and muscle cells, glucose is then stored as glycogen. In the muscle cells, breakdown of glucose supplies energy for protein metabolism , and in fat cells, the breakdown of glucose supplies glycerol for the formation of fat. In all of these ways, insulin will lower the blood glucose level.

Question 35

bile

Answer 35

Bile contains bile salts that are derived from cholesterol. These emulsify fats in the small intestine and break them down into smaller fat droplets. This provides a much larger surface area that can be acted on by pancreatic lipase.

Question 36

functions of the liver (7)

Answer 36

(1) detoxifies blood by removing and metabolizing poisonous substances (2) stores iron (Fe2+) and vitamins A, D, E, K, and B12 (3) makes many plasma proteins, such as albumins and fibrinogen, from amino acids (4) stores glucose and glycogen after a meal, and breaks down glycogen to glucose to maintain glucose concentration of blood between eating periods (5) produces urea after breaking down amino acids (6) removes bilirubin, a breakdown product of hemoglobin, from the blood and excretes it in bile, a liver product (7) helps regulate blood cholesterol level, converting some to bile salts

Question 37

How is the small intestine specialized for digestion and absorption (2; expand on the second specialization)

Answer 37

The basic condition in the small intestine is optimal for digestive enzymes that are present from pancreatic juice or from secretions of the intestinal wall. These complete the process of food digestion. The surface area is especially large for effective absorption of nutrients. The walls contain fingerlike projections called villi. Each villus has an outer layer of columnar epithelial cells that have thousands of microscopic extensions called microvilli. Microvilli greatly increase the surface area of the villus for absorption of nutrients. Each villus also contains blood capillaries and small lymphatic capillary, called a lacteal. Nutrients are absorbed into these vessels.

Question 38

describe the functions of E. Coli on the colon

Answer 38

E. Coli produces vitamin K and prevent pathogenic bacteria from colonizing the intestine.